Battery-powered electric appliances with a control circuit will need a DC-DC converter to supply the control circuit when the battery voltage is not sufficiently high to supply the control circuit, for example, because the accumulator has only one cell. If the control circuit is used for measuring the charging current of the accumulator, the measured value for the charging current is distorted by the current consumption of the DC-DC converter and any other loads.
There however exists a need for a method for measuring a charging current and a simple circuit for a battery-operated small electric appliance which enables a sufficiently accurate measurement of the charging current of the accumulator.